There seems to be a problem in the calculations

When calculating the energy required, Page says we should assume a growth in energy use of 3x as the world's economies grow. He calls that "realistic".

Then when calculating the GDP he says we should assume a "drastic" reduction in output because of those evil IPCC scientists.

Finally Page assumes that even when producing 4 million wind turbines there will be no economies of scale whatsoever, instead suggests we should "multiplying our $12tn cost figure a few times at the very least".